#!/usr/bin/env python3

class A(object):
    def run(self):
        print("A is running...")

class B(object):
    def run(self):
        print("B is running...")

class C(A, B):
    pass

class D(A, B):
    pass

class E(B, A):
    pass

c = C()
d = D()
e = E()        
c.run()
d.run()
e.run()        
